When quoting a passage from another document, it is customary to format this
as a paragraph that is indented on both the left and the right margin. You
can include quotations in Org mode documents like this:

#+BEGIN_QUOTE
Everything should be made as simple as possible,
but not any simpler -- Albert Einstein
#+END_QUOTE

If you would like to center some text, do it like this:

#+BEGIN_CENTER
Everything should be made as simple as possible, \\
but not any simpler
#+END_CENTER